Differences in Ca2+ permeability of AMPA-type glutamate receptor channels in neocortical neurons caused by differential GluR-B subunit expression

Neuron. 1994 Jun;12(6):1281-9. doi: 10.1016/0896-6273(94)90444-8.


Fast excitatory synaptic transmission in the CNS is mediated by AMPA-type glutamate receptor (GluR) channels. Heterologous expression suggested that the Ca2+ permeability of these receptors critically depends on the subunit composition. Using patch-clamp techniques in brain slices, we found that the Ca2+ permeability of native AMPA-type GluRs was markedly higher in nonpyramidal (PCa/PK approximately 0.63) than in pyramidal (PCa/PK approximately 0.05) neurons of rat neocortex. Analysis of mRNA in single cells indicated that the relative abundance of GluR-B-specific mRNA was significantly lower in nonpyramidal (GluR-B/GluR-non-B approximately 0.3) than in pyramidal (GluR-B/GluR-non-B approximately 3) cells. This suggests that differences in relative abundance of GluR-B-specific mRNA generate functional diversity of AMPA-type GluRs in neurons with respect to Ca2+ permeability.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Calcium / metabolism*
  • Calcium Channels / physiology*
  • Cerebral Cortex / physiology*
  • DNA Primers
  • Gene Expression*
  • In Vitro Techniques
  • Macromolecular Substances
  • Membrane Potentials / physiology
  • Molecular Sequence Data
  • Neurons / physiology*
  • Polymerase Chain Reaction
  • Pyramidal Cells / physiology*
  • RNA, Messenger / biosynthesis
  • Rats
  • Rats, Wistar
  • Receptors, AMPA / physiology*
  • Receptors, Glutamate / biosynthesis*
  • Visual Cortex / physiology*


  • Calcium Channels
  • DNA Primers
  • Macromolecular Substances
  • RNA, Messenger
  • Receptors, AMPA
  • Receptors, Glutamate
  • Calcium